Beyond 2011
Beyond 2011: Administrative Data Sources Report: NHS
Patient Register
November 2012
Background
The Office for National Statistics is currently taking a fresh look at options for the production of
population and small area socio-demographic statistics for England and Wales. The Beyond 2011
Programme has been established to carry out research on the options and to recommend the best
way forward to meet future user needs.
Beyond 2011 is considering a range of options including census, survey and administrative data
solutions. Since ‘census-type’ solutions are already relatively well understood most of the research
is focussing on how surveys can be supplemented by better re-use of ‘administrative’ data already
collected from the public.
The final recommendation, which will be made in 2014, will balance user needs, cost, benefit,
statistical quality, and the public acceptability of all of the options. The results will have implications
for all population-based statistics in England and Wales and, potentially, for the statistical system
as a whole.
About this paper
This report presents research reviewing the scope and quality of the NHS Patient Register as a
potential source of data for use, within the Beyond 2011 Programme, by the Office for National
Statistics.
The NHS Patient Register contains a record for every person who is registered with an NHS
General Practitioner in England and Wales and, although this source of data is not designed to
specifically measure populations, it is thought to be one of the largest data sources containing
information on virtually everyone in England and Wales.
This document is the start of a series of ‘Sources’ reports to be published over coming months.
Over the course of the Beyond 2011 Programme, regular reports will be published which will focus
on the quality of potential administrative data sources.
For more information
Search Beyond 2011 @ www.ons.gov.uk or contact : beyond2011@ons.gov.uk
© Crown Copyright 2012
Beyond 2011: Administrative Data Sources Report: NHS Patient Register
Table of Contents
1
Executive Summary ............................................................................................... 2
2
Introduction ............................................................................................................ 3
3
Background ............................................................................................................ 3
4
Potential Data Source – an overview .................................................................... 4
4.1
The NHSCR ............................................................................................................. 4
4.2
The NHS Patient Register ........................................................................................ 5
4.3
Selection of Data Source.......................................................................................... 5
4.4
Data Collection: The Registration Process ............................................................... 5
4.5
Overview of the Data ONS Receives ........................................................................ 6
4.6
Quality Procedures................................................................................................... 6
5
Overview of the NHS Patient Register Data Extract............................................. 7
5.1
Data Quality ............................................................................................................. 8
5.1.1
Linkability ............................................................................................................... 13
5.2
Sex Ratios in the Extract ........................................................................................ 14
6
Comparison Between NHS Patient Register and 2011 Census Estimates ....... 15
6.1
National Level Comparison .................................................................................... 15
6.2
Local Authority Level Comparison .......................................................................... 23
6.2.1
Local Authorities with a Higher NHS Patient Register Count than the 2011 Census
Estimates ............................................................................................................... 26
6.2.2
Local Authorities with a Lower NHS Patient Register Count than the 2011 Census
Estimates ............................................................................................................... 27
6.2.3
Local Authorities with a Similar NHS Patient Register Count to the 2011 Census
Estimates ............................................................................................................... 27
6.3
Local Authority Examples ....................................................................................... 28
7
Further Considerations and Summary ............................................................... 37
8
Future Changes to the NHS Patient Register ..................................................... 37
9
Conclusions and Recommendation for use in Beyond 2011 ............................ 38
References .................................................................................................................................. 40
Appendix A: NHS Family Doctor Services Registration Form (GSM1)................................... 41
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
1
1 Executive Summary
This report presents research reviewing the scope and quality of the NHS Patient Register as a
potential source of data for use, within the Beyond 2011 Programme, by the Office for National
Statistics (ONS).
The NHS Patient Register contains a record for every person who is registered with an NHS
General Practitioner (GP) in England and Wales and, although this source of data is not designed
to specifically measure populations, it is thought to be one of the largest data sources containing
information on virtually everyone in England and Wales.
However, the number of patients on the register has exceeded ONS’s population estimates in
every year since 1961 indicating that there are ‘coverage’ issues that will need to be overcome in
order for the dataset to be of maximum use. There are a number of reasons why the Patient
Register is higher than the population estimate, but this over coverage at national level also hides
pockets of under coverage. Over coverage at the national level is most likely to result from people
who emigrate from the UK, but do not tell their GP and their record lies dormant for some time and
duplicate records. In terms of under coverage the Patient Register does not include Armed Forces
personnel who have their own medical system. There are also issues relating to the delay between
people moving and changing their GP registration that result in over coverage in the area they
have left and under coverage in the area they have moved to.
The main findings from comparing the NHS Patient register (reference date of 23 March 2011) with
2011 Census data (reference date of 27 March 2011) are:
•
at the national level the Patient Register exceeds the Census 2011 estimate by 4.3 per cent
with the bulk of this difference found for people aged between 20 and 64
•
the NHS Patient Register sex ratio, (males to females), exceeds the census sex ratio for
people aged 27 to 68 years
•
at the local authority level the NHS Patient Register count is within three per cent of the
census estimates in 41 per cent of local authorities. 75 per cent of local authorities were
within five per cent of the census estimates and 97 per cent of local authorities were within
ten per cent of the census estimates
•
there is considerable variation in the results when the data are compared by local authority,
age and sex, highlighting that the overall difference comprises a number of different issues
which impact in different ways locally
Whilst there are a number of issues with the NHS Patient Register as a source of data to support
Beyond 2011 purposes, it will be an important source for the Programme because it:
•
has a very high level of population coverage (based on a residential base).
•
has good quality data with very low levels of missing values for key variables
•
has a unique identifier (NHS number) allowing for anonymised matching with itself over
time
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
2
•
can be obtained for a comparable reference period.
•
is produced in a comparable way across all areas of England and Wales, albeit with
different processes in both countries
The NHS has changed its administrative structure over time and will do so again in the future. ONS
will continue to assess the potential impact any such changes might have on the content and
availability of the Patient Register.
In summary, the NHS Patient Register provides broad coverage of people within England and
Wales, and should prove to be an important source of data for the Beyond 2011 Programme.
2 Introduction
The principle of Beyond 2011 is relatively simple – the Programme is investigating the best way of
producing the population and small area socio-demographic statistics needed to support the
effective administration of the country. We are carrying out a programme of research looking at all
of the possible approaches to producing this data, then assessing each of these against a clear
and agreed set of criteria in order to help us decide on the best way forward.
This document, (S1): Administrative Data Sources Report (Patient Register), is the first in a series
of detailed assessments setting out the results of reviews of individual sources. We anticipate that
further reports will be published including:S2: Administrative Data Sources Report (Household Electoral Registration)
S3: Administrative Data Sources Report (School Census for England and School Census for
Wales)
S4: Administrative Data Sources Report (Higher Education Student Data); and
S5: Administrative Data Sources Report (Department for Work and Pensions/HM Revenue and
Customs Customer Information System - initial assessment)
In making use of data from administrative sources attention must be given to understanding the
processes and procedures associated with the collection, collation, processing and validation of
the information and the implications these processes may have for the underlying quality of the
data. In particular, it is important to take account of the differences between data collected for
administrative and statistical purposes and, where necessary, to make allowances for differences
in data definitions and classifications as well as variations in timeliness and reference points.
This report brings together this information with a quantitative comparison of the Patient Register
and the 2011 Census to inform the use of this dataset within the Beyond 2011 Programme.
3 Background
All of the indications are that the census held in 2011 has been highly successful – but there are
clear signs that taking the census is becoming increasingly challenging and costly.
The dynamic nature of populations, advances in information technology and demand for more
frequent and more detailed statistics are driving changes in methods. This trend can be seen
across many developed countries.
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
3
ONS set up the Beyond 2011 Programme in April 2011 to take a fresh look at options for meeting
future user needs for population and small area socio-demographic statistics.
The Beyond 2011 Programme is studying a range of statistical options including:
•
•
•
census-type solutions
administrative data solutions
survey solutions
Since census type solutions are already relatively well understood the majority of the Programme’s
research work is focussed on investigating ways of making more use of existing administrative
datasets combined with targeted surveys. Recommendations on the way forward, to be made in
2014, will be informed not only by the statistical viability of the potential solutions, but also by a full
understanding of user requirements, public burden, costs and public acceptability.
Evaluating the quality of administrative data sources that may be used within the Beyond 2011
programme is a key element of the research. The outcomes will inform the benefits and challenges
associated with using these data sources. The NHS Patient Register is one such administrative
source. ONS has access to an extract of demographic information from the NHS Patient Register.
It contains a record for every person who is registered with a GP in England and Wales. Due to its
broad coverage of persons in England and Wales, the NHS Patient Register could prove to be a
key source of data for the Beyond 2011 Programme.
4 Potential data source – an overview
There are two administrative sources available to ONS dealing with persons registered for medical
services. These are;
4.1
•
the NHS Central Register, (NHSCR), a centralised system for patient administration, and
•
the National Health Service (NHS) Patient Register, a detailed list of patients with
additional geographical details. Primary Care Trusts (PCTs) are currently responsible for
maintaining the NHS Patient Register in England with the NHS Wales Shared Services
Partnership responsible for Wales.
The NHSCR
The NHSCR provides a comprehensive system to assist with NHS patient administration in
England and Wales. Responsibility for the register transferred from ONS to the NHS Information
Centre (NHSIC) on April 1st 2008 (NHS 2009). The register contains broad, but not complete,
coverage of the population of England and Wales. Updates occur as a result of weekly
submissions of new births and deaths from the Registrars of Births and Deaths, and for new
registrants with GPs (such as migrants). It is also routinely updated with details of name changes,
immigration, enlistments to Armed Forces, adoptions, entries into service medical officer care and
cancer registrations. The Administrative Data Liaison Service estimate approximately 9 million
changes are made to the NHSCR each year, including the creation of around 600,000 new records
per year (Administrative Data Liaison Service 2012).
The work of the NHSCR covers a range of services, including recording the transfer of patients
between health authorities. Each record in the extract of the register provided to ONS contains the
patient’s NHS number, forename and surname, date of birth and date of acceptance by the health
authority. As of 2006, PCTs replaced health authorities as the main health geography in England.
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
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4.2
The NHS Patient Register
The coverage of the NHS Patient Register is all persons registered with a GP in England and
Wales 1. The NHS Patient Register is used to maintain an accurate list of all persons registered
with a GP, allowing the timely transfer of medical records and correct payments to doctors. It
contains a list of everyone who is, or ever has been, registered with a GP in England and Wales
since the NHS was founded in July 1948 (NHS 2009). Although this source of data has a specific
administrative purpose and is not designed to specifically measure the population, it is thought to
be one the largest data sources containing information on virtually everyone in England and Wales.
The NHS Patient Register extract provided to ONS currently contains approximately 58 million
records, extracted from 87 separate National Health Applications and Infrastructure Services
(NHAIS) sites; 82 of which are in England and 5 of which are in Wales. Every NHAIS site holds a
register of the patients registered with GPs within their area of responsibility. The register contains
a number of variables including the NHS number, gender, date of birth, date of acceptance at the
health authority and unit postcode of the address of each patient. It does not contain any
information about the health of patients.
4.3
Selection of data source
The NHS Patient Register is a complete list of all persons registered with a GP in England and
Wales whereas the NHSCR extract currently available to ONS relates only to changes which have
taken place over the year, e.g. an address change or a change in GP, rather than a complete
register of all patients. It has therefore been decided to focus on the NHS Patient Register as it is
more suitable for Beyond 2011 purposes, in our research to estimate the size of the population.
4.4
Data collection: the registration process
The registration process begins when a patient attends a GP surgery and asks to register with a
GP. The patient is usually asked for their medical card and for their date of birth; gender; current
address and postcode; name of their last GP; and previous address and postcode. The patient is
also asked whether they have come from abroad.
If the patient is accepted onto the register (the default is to accept), the registration will proceed by
the information being sent to the PCT (for England) or the NHS Wales Shared Services
Partnership (for Wales) either on paper via NHS form GMS1 (see Appendix A) or electronically via
a system known as GP Links.
At regular intervals - usually weekly - GP practices notify the PCTs (for England) or the NHS Wales
Shared Services Partnership (for Wales) of new patients. These are processed by the PCT or the
NHS Wales Shared Services Partnership with the patient records being checked to see whether
the person is already present on the local database. If the person is new to the area, NHSCR are
informed so that medical records can be obtained.
The NHS number is intended to be unique. There are, however, a small number of cases where
the NHS number is duplicated across records (See section 5.1 below).
1
Whilst responsibility for the NHS in Wales is devolved, the information is provided to ONS along with
information for England by NHS Connecting for Health
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
5
4.5
Overview of the data ONS receives
ONS obtains a copy of PCT registers on an annual basis 2 and combines these to create an
integrated dataset for England and Wales. ONS uses the Patient Register dataset to measure
internal migration; as part of the calculation of the mid-year population estimates; and within the
ONS longitudinal study 3. Patient Register data were also used as part of the process of quality
assuring the 2011 Census results. For internal migration purposes downloads are taken on 31st
July to enable migration estimates to be made for the year ending 30th June, allowing a months
delay for registrations following moves before 30th June.
Agreement was reached with the NHSIC for additional ‘Enhanced’ NHS Patient Register (EPR)
extracts in June 2010. The EPR extract contains the following additional variables: surname;
forename; other forenames; address – up to five separate lines. These additional variables make it
possible for ONS to perform linkage with completely ‘anonymised’ data between the EPR and
other administrative data sources (see section 5.1). Analyses in the present report were performed
using the EPR dataset which was supplied to ONS on 23 April 2011.
4.6
Quality procedures
Some quality checks are carried out by the NHS Connecting for Health (CfH) prior to releasing an
extract to ONS. Details on these are given below.
i)
Identification of temporary records
Temporary records are created for NHS patients receiving treatment in an area that is not their
usual residence. They can be identified because they are issued with a temporary NHS
number. These patients can appear more than once on the NHS Patient Register and so
records with a temporary NHS number are removed from the register before any further
processing is done.
ii)
Identification of records with incomplete data
As part of the validation process, records are identified which fail a basic range or validation
check. Records that fail basic checks are written to a separate file and are referred to as
incomplete records.
iii)
National Duplicate Registration Initiative (Audit Commission)
The Audit Commission periodically carry out a data cleaning exercise. National Duplicate
Registration Initiatives (NDRI) have previously been undertaken in 1999, 2004 and 2009 and
are the only occasions when the full NHS Patient Register is subjected to a de-duplication
process(Audit Commission 2012). The prime reason for these exercises is to address list
inflation. List inflation is a financial concern for the NHS as the number of people on the NHS
Patient Register in any given area determines the amount of funding provided to GPs in that
area. Thus, for every erroneous record on the NHS Patient Register, a set fee will be paid to
the GP site to which that record is associated. The NDRI carried out in 2004 resulted in almost
2
3
ONS has had legal access to NHS Patient Register data since 1999.
See ONS Longitudinal Study for more details
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
6
185,000 patient records being removed from the patient register. These deleted records were
categorised as follows: duplicate records (34 per cent); deceased persons (22 per cent); ‘gone
aways’ (persons identified as having moved out of the area) (28 per cent); age reports (eight
per cent); temporary NHS numbers (seven per cent); removed asylum seekers (one per cent),
(Audit Commission 2006).
For the most recent exercise in 2009/10 approximately 58 million patient records were extracted
from the NHAIS system. The NDRI 2009/10 produced more than 750,000 data matches of which
95,000 records were removed; representing 0.16 per cent of the total number of records extracted
for the exercise. The deleted records were categorised as follows 4: Deceased persons (34 per
cent); Duplicate records (31 per cent); multiple occupancy (ten or more at an address) (21 per
cent); removed asylum seekers (ten per cent); Age reports (four per cent), (Audit Commission
2012).
While not all deleted record categories can be directly compared between NDRI 2004 and 2009,
the Audit Commission (2012) still concluded that the reduction in the total number of deleted
records, (from 185,000 in NDRI 2004, to 95,000 in NDRI 2009), is evidence that patient register
data quality has improved between 2004 and 2009.
4
Note ‘temporary NHS number’ and ‘gone away’ matching was not undertaken in NDRI 2009 whereas ‘multiple
occupancy matching’ was introduced only in NDRI 2009 (Audit Commission 2012).
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
7
5 Overview of the NHS Patient Register data extract
Figure 1 shows the number of records in the April 2011 NHS Patient Register dataset for persons
aged 0-84 with notable features being:
(i)
an upward spike in frequency for persons aged 61-63 years which corresponds to the
baby-boom in the years immediately after World War Two (1946-1948);
a dip in frequency for those aged 32-38 reflecting the lower birth rate between 1973 and
1979 and;
the increase in births in the last decade is seen for those aged 0-10.
(ii)
(iii)
Figure 1. 2011 NHS Patient Register of England & Wales by total persons
1000
900
Population (thousands)
800
700
600
500
400
300
200
100
0
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
Age
Source: NHS Patient Register 2011.
5.1
Data quality
Once ONS receive the data a number of quality checks are carried out. The following section
details some checks and the resulting implications for the Beyond 2011 Programme where
applicable.
Duplication
The last NDRI was carried out in 2009/10 (Audit Commission 2012). Despite this, ONS needed to
remove a number of duplicates which existed in the 2011 EPR data and thus it would appear that
some duplication is still present in the data extract.
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
8
ONS collated the 87 supplied files which made up the April 2011 EPR extract, resulting in a total of
58,509,255 records. Of these, 22,122 duplicate records were identified by de-duplicating on the
supplied NHS number unique identifier and retaining the most recently updated record. These
22,122 duplicate records were then examined to identify those where the year of birth differed from
that recorded on the retained record. 364 were found to fulfil this criterion, and of these 41
duplicate NHS numbers were found which referred to a different record than the retained record.
These records were reinstated in the data set. The remaining 323 records in the set could
reasonably be judged to refer to the same people, although these records did include minor
discrepancies in the date of birth variable. The final total was 58,487,174. Table 1 summarises this
information.
Table 1: Duplicate NHS Number analysis
Record count
58,509,255
22,122
364
Initial record count
Duplicate NHS Numbers found
Duplicate NHS Numbers where associated dates of birth
do not match
Duplicate NHS Numbers that do not refer to same
41
person*
* Records were classified as not belonging to the same person where the recorded
name was different or there were minor differences between names and significant
ones between dates of birth.
Source: NHS Patient Register 2011.
Missing data
Table 2 shows the percentages of missing/non-missing data, in the April 2011 EPR extract, for
each of the twelve variables which are considered as potentially key for Beyond 2011 purposes. As
Table 2 indicates, there are no missing data for NHS numbers; Gender; Surname; Forename and
the fourth address line. Further there are just 2 missing values for date of birth. A small number of
postcodes are missing but this represents less than 0.01 per cent of the total records in the NHS
Patient Register. The largest instances of missing data are amongst four of the five address fields
(range 2.1 per cent - 80.5 per cent missing data). There is no missing data for the Address4
variable and this is likely to be because the fourth address line typically contains the name of the
postal town or city in which the patient is resident and this is a mandatory field when creating a
record in the Patient Register.
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
9
Table 2. April 2011 Extract - Enhanced Patient Register Key Variable
completeness
Variable name
Variable type
Non-missing April 2011
Missing April 2011
(per cent)
(per cent)
58,487,172
2
DateOfBirth
Numeric
(99.99)
(0.01)
58,487,174
0
NHSNumber
Character
(100.0)
(0.0)
58,487,174
0
Gender
Character
(100.0)
(0.0)
58,487,174
0
Surname
Character
(100.0)
(0.0)
58,487,174
0
Forename
Character
(100.0)
(0.0)
8,672
58,478,502
Postcode
Character
(99.99)
(0.01)
11,397,125
47,090,049
Address1
Character
(19.49)
(80.51)
57,268,749
1,218,425
Address2
Character
(97.92)
(2.08)
30,965,608
27,521,566
Address3
Character
(52.94)
(47.06)
58,487,174
0
Address4
Character
(100.0)
(0.0)
16,863,351
41,623,823
Address5
Character
(71.17)
(28.83)
Source: NHS Patient Register 2011.
Coverage issues
There is evidence that the NHS Patient Register is subject to both over coverage and under
coverage. In April 2011 the NHS Patient Register record count (58,471,500) was 4.3 per cent
greater than the 2011 Census population estimate (56,075,900) of England and Wales (ONS
2012a). Similarly, the number of patients on the registers has exceeded the number of people
resident in the country when compared to ONS Mid-Year Estimates, in every year since 1961
(Scott & Kilbey, 1999). Possible reasons for over coverage are that some patients are registered in
more than one area; some patients may have more than one NHS number and finally that some
patients remain on the NHS Patient Register after leaving the country and/or having died (Audit
Commission 2012). Additionally some people are eligible to register with a GP that would not be
included in the ONS definition used for producing the population estimates. Some of the main
reasons for coverage issues can be categorised as follows:
•
multiple area registrations: the current registration system does not require a ‘new’
patient to provide proof of identification to support their registration. Therefore, the
possibility exists for successful applications being made by a single person, but at different
GP sites. For example, a person who is registered with a GP in Hampshire permanently
moves to a house in Lancashire and registers with a GP near their new residence.
However, when registering they provide information which is sufficient to allow them to
register with their new GP, but insufficient to allow the GP site to identify the person as
being already on the NHS Patient Register, e.g. due to the person spelling their name
differently to how it appears on the NHS Patient Register and/or by providing a date of birth
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
10
in an ambiguous date format DD-MM-YY / MM-DD-YY; (e.g. 01-03-73 versus 03-01-73). In
this instance it is possible that a new record, with a new unique NHS number could be
created, meaning this person would then have two separate records, with two different NHS
numbers, on the NHS Patient Register
5
6
•
duplicate NHS number: records which have a duplicate NHS number can occur in one of
two ways. The first type of duplicate is two or more identical records, the majority of which
are thought to occur temporarily, at any given point in time, where a person is in the
process of transferring from one GP to another (Audit Commission 2012). The second type,
the cause of which is unclear, is where the records of two different people have the same
NHS number. According to the Audit commission this applies to a small number of records
but was highlighted as a data quality issue (Audit Commission 2012)
•
lags in the recording of births, deaths and migrants on the NHS Patient Register 5:
potential time delays in notification or no notification of events (births, deaths, internal and
international moves) can lead to patients remaining on registers when they should be
removed or in the case of births or immigration, not appearing on the list straight away.
Below are some details on different event notification procedures
o
births: NHSCR are responsible for distributing NHS numbers to the Registrars of
Births and Deaths (RBDs), who, in turn, allocate them as each new birth is
registered. Sometimes the RBDs report the births directly to the health authority, but
usually it is the parent who registers the child with a GP. As some parents may take
longer to do this than others there may be a lag where a child may not appear on
the register for a number of weeks or months after being born. Further, if a child is
registered solely for private healthcare they will not appear on the NHS Patient
Register at all resulting in under coverage.
o
deaths: currently NHAIS sites receive notifications of patient deaths from the
Personal Demographics Service National Back Office, which links the General
Register Office register of recorded deaths to patient lists (Audit Commission 2012).
However, some NHAIS sites have expressed concern that they do not have a
system in place that checks for patients who have died whilst abroad. As a result,
some persons who die whilst abroad may not be removed from the NHS Patient
Register and cause over coverage (Audit Commission 2012).
o
embarkations: NHSCR receives details of embarkations 6 from people handing in
their medical cards and from the Department of Work and Pensions, Home Office
and Immigration officers. However, if somebody does not inform the authorities that
they have emigrated, or intend to emigrate, it is likely that they will remain on the
NHS Patient Register after leaving the UK, leading to over coverage. There is also
a clear incentive for emigrants to remain on the NHS Patient Register as it allows
them to access health care services, free of charge, should they return temporarily
to the UK; e.g. to visit relatives.
o
international migrants: international migrants may not register with a GP when
they arrive in England or Wales. Some may not register at all. Further discussion
on this can be found in the definitional differences section below.
See Smallwood and Lynch (2010) for more details on the issue of lags.
People leaving the country.
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
11
•
geographical variations in data quality: NHS systems are administered on a regional
basis and inevitably there is variation in quality between regions. This is also true at the
country level as the NHS Patient Register is administered by different bodies for England
and Wales. This could cause small differences in data quality between the two countries.
In addition the NHS is devolved in Wales, which may result in long term risk of any different
changes in policy, management or processes, which could lead to future incomparability
between England and Wales. Even at the local level there is likely to be variation between
GP sites in efficiency of record keeping. Data quality initiatives, such as identifying multiple
registrations and cancelling student registrations, implemented by NHS Information
Systems also vary geographically, for example in terms of the regularity with which data
quality programmes are implemented. This is likely due to the availability of resources, e.g.
financial, available personnel and technical expertise, differing from one area to another
(Audit Commission 2012).
•
definition differences - definition of usually resident: according to ONS (2009) a usual
resident of the UK (for census output purposes only) is anyone who, on 27 March 2011 was
(i) in the UK and has stayed or intended to stay in the UK for a period of 12 months or more
or; (ii) had a permanent UK address and was outside the UK and intended to be outside the
UK for less than 12 months. There are many reasons why a person may appear on the
NHS Patient Register but not be deemed as usually resident, according to the census
definition. For example, a person may register with a GP, and thus appear on the NHS
Patient Register irrespective of whether they intend to stay in the UK for at least 12 months.
The relationship between the population covered in the NHS Patient Register and the usual
resident population is illustrated in Figure 2. Here, we see that for a specific area at a
specific time, the population covered in the NHS Patient Register may differ from the usual
resident population as a result of: the inclusion of persons staying in England and Wales for
less than 12 months; the omission of persons who are not registered with a GP; people
remaining registered after they have emigrated or died; erroneous list cleaning (removing
patients when they have not moved); issuing a new NHS number to someone who is
already on the list and lags in international migrants registering with a GP.
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
12
Figure 2. Relating the NHS Patient Register to the Usual Resident Population in Area j at
Time t
Failure to de-register
or registration lag for
out-migrants
Linkability
The NHS number is unique enough to allow longitudinal linking of the NHS Patient Register with
itself. However, as NHS numbers are not included on any other administrative data source
available to ONS, linkage between administrative sources using NHS number will not be possible.
Despite this, linkage may still be possible by using combinations of other variables such as
surname, date of birth and address information. It is recognised that this raises concerns relating to
the privacy of data about individuals and households and that steps need to be taken to ensure
confidentiality of any data used. For this reason, Beyond 2011 is currently developing methods to
enable linkage with completely ‘anonymised’ data through a number of pre-processing steps. The
results of research to date are very promising and have been applied to current research. We will
be discussing our approach with experts over the next few months and will publish more details of
the methods in 2013.
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
13
5.2
Sex ratios in the extract
Figure 3 shows the ratio of men to women on the NHS Patient Register for years 2001, 2006 and
2011. Sex ratios are often used as a quality measure of data by age and sex as they are
independent of the absolute numbers of males and females in a large population (Smallwood & De
Broe 2009). Figure 3 shows the sex ratios at the younger ages as fairly consistent and as
expected from a large Western developed country (around 105 boys per 100 girls). However from
the age of 18 a dip is seen in the sex ratio which peaks around the age of 23. This dip in the sex
ratio is apparent in the three years studied (2001, 2006 & 2011) and thus it can be concluded that
the dip is not ageing forwards. From this dip the sex ratio rises to a bulging profile from age 30 to
65 years.
This dip in the national sex ratio is primarily determined by international migration. Previous
research has focused on the trends in the NHS Patient Register sex ratio for this specific age
group and found the sex ratio to be driven primarily by the registration and de-registration of female
migrants (Smallwood & De Broe 2009). An increase in female migrants registering at specific age
groups could cause a lower sex ratio for these same age groups. In contrast, the de-registration of
female migrants, at other age groups, could produce a higher sex ratio for these same age groups.
Previous research conducted by ONS found females to be more compliant with administrative
requirements and to register with a GP on arrival at the new location (Smallwood & De Broe 2009).
The ‘bulging’ profile in the NHS Patient Register above the age of 30 may be the result of delays in
male migrants registering at a GP practice and/or male emigrants not being deregistered when
they leave the UK.
Figure 3. Sex Ratios of the NHS Patient Register for England & Wales for years 2001, 2006
& 2011
110
Ratio (number of men per 100 women)
100
90
80
70
60
50
40
2001
30
2006
20
2011
10
0
0
5
10
15
20
25
30
35
40 45
Age
50
55
60
65
70
75
80
Source: NHS Patient Register 2001, 2006, 2011.
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
14
6 Comparison between NHS Patient Register and 2011 Census estimates
In this section the NHS Patient Register count is compared with the 2011 Census population
estimates at both the national and local authority level.
The following analysis looks at the comparison of the 2011 Census population estimates
(reference date of 27 March 2011) and the 2011 NHS Patient Register count (reference date of
23rd April 2011).
6.1
National level comparison
Total population
At the England and Wales national level, the 2011 NHS Patient Register count is greater than the
2011 Census estimates by 4.3 per cent (ONS 2012a).
Figure 4. 2011 NHS Patient Register count versus 2011 Census estimates for England &
Wales by total persons
1000
900
800
Population (thousands)
700
600
500
400
300
Patient Register
200
Census
100
0
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
Age
Source: NHS Patient Register 2011, Census 2011
Figure 4 shows a comparison of the age distribution of the two sources. It can be seen that there is
a good correspondence from nought to 20 years. From 20 years onwards, the NHS Patient
Register count exceeds that of the 2011 Census estimates, with a bulging pattern between the
ages 20 and 64. At this point the lines meet again. This pattern supports the suggestion presented
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
15
in the first part of this report that the NHS Patient Register is subject to net over coverage and
therefore a greater count is seen on the NHS Patient Register than that of the resident population.
When comparing the two sources at the England national level (Figure 5), the 2011 NHS Patient
Register count is greater than the 2011 Census estimates by 4.3 per cent (ONS, 2012a). The age
distribution, for both sources follow a similar pattern to that seen at the England and Wales national
level.
Figure 5. 2011 NHS Patient Register count versus 2011 Census estimates for England by
total persons
1000
900
Population (thousands)
800
700
600
500
400
Patient Register
300
Census
200
100
0
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
Age
Source: NHS Patient Register 2011, Census 2011.
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
16
When comparing the two sources at the Wales national level (Figure 6), the NHS Patient Register
count is greater than the 2011 Census estimates by 3.1 per cent (ONS 2012a). The differences
between the two sources follow a similar pattern to that seen for England, although the differences
between the two sources are smaller than those seen for England. This could suggest that the
Patient Register in Wales experiences less net over coverage than the Patient Register for
England.
Figure 6. 2011 NHS Patient Register count versus 2011 Census estimates for Wales by total
persons
50
Population (thousands)
40
30
20
Patient Register
10
Census
0
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
Age
Source: NHS Patient Register 2011, Census 2011
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
17
Figure 7 shows a comparison between the 2011 NHS Patient Register and the 2011 Census
estimates for men in England and Wales. It can be seen that between the ages of 0 and 21, the
two sources are very similar. However, between the ages of 22 and 63, the NHS Patient Register
has a higher count of men compared to the 2011 Census estimate. Lastly, between ages 64 and
84 the two sources are again very similar.
Figure 7. 2011 NHS Patient Register versus 2011 Census estimates for England and Wales
by males
500
450
Population (thousands)
400
350
300
250
200
150
Patient Register Males
100
Census Males
50
0
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
Age
Source: NHS Patient Register 2011, Census 2011
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
18
Figure 8 shows a comparison between the 2011 NHS Patient Register count and the 2011 Census
estimates for women in England and Wales. It can be seen that between the ages of 0 and 19, the
two sources are very similar. However, between the ages of 20 and 48, the NHS Patient Register
has a higher count of women compared to the 2011 Census estimate. Lastly, between ages 49
and 84 the two sources are again very close.
Figure 8. 2011 NHS Patient Register count versus 2011 Census estimates for England and
Wales by females
500
450
Population (thousands)
400
350
300
250
200
150
Patient Register Females
100
Census Females
50
0
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
Age
Source: NHS Patient Register 2011, Census 2011.
Comparing Figures 7 and 8, it is apparent that there is a greater difference between the two
sources for men than for women and that this difference is spread out over a wider age range for
men (22-63 years) than for women (20-48 years). This difference can be seen at both the England
national level and the Wales national level.
Section 5 of this report examined in detail some of the reasons why the 2011 Census estimates
and the NHS Patient Register counts are likely to differ. Two of the reasons identified those of
multiple registrations and lag in registration, are likely to go some way towards explaining why
there are larger differences for men than for women. In particular, the larger difference between the
two sources accounted for by men could be a result of men being slower to register/re-register with
a GP than women, and men being less likely to de-register when they leave the country. These
differences will be important when considering how the NHS Patient Register can be used within
the context of Beyond 2011.
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
19
Sex ratios at the national level
Figure 9 compares the sex ratios in the 2011 NHS Patient Register against those of the 2011
Census estimates for England and Wales. The sex ratios for both sources follow a similar pattern
for the ages 0 to 19. At this point 2011 Census estimates show a slightly higher sex ratio up to the
age of 26. At 27 years the lines cross and the 2011 NHS Patient Register sex ratio exceeds the
2011 Census sex ratio with a bulging pattern up to the age of 68. From age 68 onwards the sex
ratios show a similar pattern again.
This variation in the sex ratio for the NHS Patient Register is likely to be caused by international
migration. The dip in the NHS Patient Register for the ages 18 to 24 is likely to be due to more
female migrants than male migrants registering with a GP when they arrive in the country.
However, as these migrants leave the country, if it is the case that female migrants are more likely
to deregister, (as discussed earlier), but the male migrants remain on the register; this would result
in the pattern seen from the age of 27 onwards. This is compounded by a higher de-registration
rate for UK national women who emigrate as compared with UK national men. This will cause over
coverage in the NHS Patient Register for some age groups. The census sex ratios show a more
consistent pattern across its age groups as would normally be expected, (Smallwood & De Broe
2009).
Figure 9. Sex ratios from 2011 NHS Patient Register & 2011 Census estimates for England &
Wales
110
Ratio (number of men per 100 women)
100
90
80
70
60
50
40
Patient Register
30
Census
20
10
0
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
Age
Source: NHS Patient Register 2011, Census 2011
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
20
Figure 10 compares the sex ratios in the 2011 NHS Patient Register against those of the 2011
Census estimates for England. The sex ratios for both sources follow a similar pattern to that at the
England and Wales national level.
Figure 10. Sex ratios from 2011 NHS Patient Register & 2011 Census estimates for England
110
Ratio (number of men per 100 women)
100
90
80
70
60
50
40
Patient Register
30
Census
20
10
0
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
Age
Source: NHS Patient Register 2011, Census 2011.
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
21
Figure 11 compares the sex ratios in the 2011 NHS Patient Register against those of the 2011
Census estimates for Wales. Overall, the sex ratios for both sources follow a similar pattern to that
at the England and Wales national level. However the dip at the 18-24 year olds is not as distinct
as that at the England national level. The bulging pattern that is seen in the England sex ratios
from the ages of 27 to 68 is still seen in the Wales national graph but again is less prominent than
that at the England level.
Figure 11 Sex Ratios from 2011 NHS Patient Register & 2011 Census Estimates for Wales
110
Ratio (number of men per 100 women)
100
90
80
70
60
50
40
30
Patient Register
20
Census
10
0
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
Age
Source: NHS Patient Register 2011, Census 2011.
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
22
6.2
Local Authority Level Comparison
When comparing the NHS Patient Register count with the 2011 Census estimates at the local
authority level, (Figure 12), the NHS Patient Register count is within three per cent of the census
estimates in 41 per cent of local authorities in England and Wales. 75 per cent were within five per
cent of the census estimates and 97 per cent were within ten per cent of the census estimates.
For those local authorities who had a difference between the two sources of greater than three per
cent, analysis shows that the majority of these local authorities had a NHS Patient Register count
which was higher than the census estimates.
Figure 12. Percentages of Local Authorities in the 2011 NHS Patient Register counts,
presented as a percentage difference to Census estimates
45
40
35
Percentage
30
25
20
15
10
5
0
Under 10 to
19.9%
Under 5 to
9.9%
Under 3 to
4.9%
Within 3%
Over 3.4.9% Over 5-5.9%
Over 1019.9%
Source: NHS Patient Register 2011, Census 2011
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
23
Map 1 shows the comparison between the 2011 NHS Patient Register count and the 2011 Census
estimates, by local authority, across England and Wales. Differences between the NHS Patient
Register count and the 2011 Census estimates are much more variable across the local authorities
and therefore it can be concluded that this variation is dependent on particular local circumstances.
Map 1 highlights the difference between England and Wales when comparing the NHS Patient
Register count with the 2011 Census estimates. When comparing the two sources at the local
authority level, the NHS Patient Register count is within three per cent of the census estimates in
40 per cent of local authorities in England and 59 per cent of local authorities in Wales. This
pattern supports the suggestion presented in section 6.1 that the NHS Patient Register in England
is subject to a higher net over coverage count than the NHS Patient Register in Wales.
Forest Heath and Richmondshire, (the two dark brown shaded areas in map 1) show the census
being more than ten per cent higher than the NHS Patient Register. Both of these local authorities
have a significant Armed Forces population and this is likely to be the reason behind this
difference. Armed Forces and the NHS are discussed further in section 6.2.2.
Map 1 also shows that the local authorities where the NHS Patient Register count falls within three
per cent of the 2011 Census estimates are often in rural areas where the population is likely to be
less mobile. These areas are unlikely to experience as much turnover on the NHS Patient
Register as urban ones, as the population remains fairly static and are therefore at less risk of
coverage issues.
Map 1 indicates that the local authorities that experience more than a three per cent difference
between the NHS Patient Register count and the census estimates are often in large urban areas.
The map shows London, Manchester, Liverpool, Birmingham and Cardiff to be within this category.
Possible reasons for this are discussed in the next section.
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
24
Map 1. Percentage difference between the 2011 NHS Patient Register count and the 2011
Census estimates by local authorities in England and Wales, for total persons
Source: NHS Patient Register 2011, Census 2011
Contains National Statistics data © Crown copyright and database right 2012
Contains Ordnance Survey data © Crown copyright and database right 2012
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
25
6.2.1
Local authorities with a higher NHS Patient Register count than the 2011 Census
estimates
The majority of local authorities show higher NHS Patient Register counts than the 2011 Census
estimates. Those local authorities which have the largest difference between the two sources are
characterised as being large urban areas, with eight London boroughs being within the top ten
local authorities with the highest percentage difference (see Figure 13).
Figure 13. Top ten local authorities in England and Wales where the 2011 NHS Patient
Register count is greater than the 2011 Census estimates
20
18
Percentage difference
16
14
12
10
8
6
4
2
0
Blackpool
Ealing
Merton
Lewisham
Wandsworth
Newham
Brent
Oxford
Southwark
Lambeth
Source: NHS Patient Register 2011, Census 2011
High levels of migration (both internal and international) are often seen in large urban areas. High
levels of international migration can result in over coverage on the NHS Patient Register as
discussed in section 5.1. Obviously in areas where there are higher levels of international migration
the risk of this over coverage is far greater than areas of low international migration. In the areas
where the NHS Patient Register count is higher than the 2011 Census estimate there are higher
proportions of short-term migrants than in the areas where the NHS Patient Register is lower than
the census estimates, (ONS 2012b). Oxford is shown to have the third highest positive percentage
difference compared to the 2011 Census estimates. Oxford is not a large urban area like London;
however, it does experience one of the highest levels of international migration in England and
Wales (ONS 2012b).
Coverage issues can also occur when a person moves from one local authority to another as they
may not register with a new GP for a significant time period. They will also probably have not
deregistered from their GP in their previous local authority. This will cause an under count in one
local authority and an over count in the other.
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
26
6.2.2
Local authorities with a lower NHS Patient Register count than the 2011 Census
estimates
There are a small number of local authorities which show a lower count in their 2011 NHS Patient
Register than in their 2011 Census estimates. Figure 14 shows that the local authorities of
Richmondshire and Forest Heath experience the largest negative difference when comparing the
2011 Census estimates and the 2011 NHS Patient Register. Both of these local authorities contain
large Armed Forces bases. Hambleton (bordering Richmondshire), St Edmundsbury (bordering
Forest Heath), Gosport (Naval) and Wiltshire (Army) also see a negative difference when
comparing the two sources.
Figure 14. Top ten local authorities in England and Wales where the 2011 NHS Patient
Register count is lower than the 2011 Census estimates
0
Percentage difference
Wiltshire
Tunbridge Wells
North Kesteven
Hambleton
Shropshire
Gosport
Rutland
St Edmundsbury
Forest Heath
-4
Richmondshire
-2
-6
-8
-10
-12
-14
-16
Source: NHS Patient Register 2011, Census 2011.
The Armed Forces personnel are counted in the 2011 Census estimates as they are defined as
part of the resident population. In contrast, Armed Forces (and in some cases their dependents)
are not seen on the NHS Patient Register as they have their own military health services. This
exclusion of the Armed Forces personnel from the NHS Patient Register highlights one of the
issues of using an administrative source, designed for another purpose, to measure the resident
population. Consequently the NHS Patient Register does not have complete coverage of the entire
resident population as illustrated in section 5.1.
6.2.3
Local authorities with a similar NHS Patient Register count to the 2011 Census
estimates
There are a number of local authorities which show some level of accord between the 2011 NHS
Patient Register count and the 2011 Census estimates. Without the benefit of record-level data
linking it is not clear whether this does show complete agreement between the actual residents of
the area or just coincidental numbers, but it is likely to reflect a higher level of agreement in the
data than elsewhere. The majority of the areas showing less than a one per cent difference
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
27
between the NHS Patient Register count and the 2011 Census estimates are rural or
comparatively sparsely populated areas.
6.3
Local authority examples
When comparing the 2011 NHS Patient Register count with the 2011 Census estimates, the extent
of the difference between the two sources can be affected by a number of factors, e.g. sex, age,
local circumstances. The following maps are shown to highlight some of the differences that exist
across the local authorities within England and Wales, by sex and selected age groups.
Maps 2 and 3 show the difference between the 2011 NHS Patient Register count and the 2011
Census estimates for men and women respectively aged 20-24. The majority of local authorities
show higher counts for the 2011 NHS Patient Register than the 2011 Census estimates, for both
men and women, in this age group.
There are a small number of local authorities which show the 2011 Census estimates as being
higher than the 2011 NHS Patient Register count. This difference is more common for men than it
is for women. For men, 22 per cent of local authorities show a higher count for the 2011 Census
estimates compared to the 2011 NHS Patient Register. This is in contrast to only nine per cent of
local authorities for women.
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
28
Map 2. Percentage difference between the 2011 NHS Patient Register and the 2011 Census
by local authorities in England and Wales by males aged 20-24 years
Source: NHS Patient Register 2011, Census 2011
Contains National Statistics data © Crown copyright and database right 2012
Contains Ordnance Survey data © Crown copyright and database right 2012
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
29
Map 3. Percentage difference between the 2011 NHS Patient Register and the 2011 Census
by local authorities in England and Wales by females aged 20-24 years
Source: NHS Patient Register 2011, Census 2011
Contains National Statistics data © Crown copyright and database right 2012
Contains Ordnance Survey data © Crown copyright and database right 2012
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
30
Maps 4 and 5 show the comparison between the 2011 NHS Patient Register count and the 2011
Census estimates for men and women respectively, aged 40-44. For 40-44 year old men the
majority of local authorities show a difference between the two sources as being between three to
ten per cent. However, in some urban local authorities a difference of more than ten per cent is
seen e.g. some local authorities within Greater London. This pattern is not the same for women,
where the majority of local authorities see the difference between the NHS Patient Register and
the census estimates as being within three per cent of each other. For women there are only three
per cent of local authorities which have a difference of more than ten per cent between the two
sources compared to 41 per cent of local authorities for men.
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
31
Map 4. Percentage difference between the 2011 NHS Patient Register and the 2011 Census
by local authorities in England and Wales by males aged 40-44 years
Source: NHS Patient Register 2011, Census 2011
Contains National Statistics data © Crown copyright and database right 2012
Contains Ordnance Survey data © Crown copyright and database right 2012
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
32
Map 5. Percentage difference between the 2011 NHS Patient Register and the 2011 Census
by local authorities in England and Wales by females aged 40-44 years
Source: NHS Patient Register 2011, Census 2011
Contains National Statistics data © Crown copyright and database right 2012
Contains Ordnance Survey data © Crown copyright and database right 2012
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
33
Maps 6 and 7 show the comparison between the 2011 NHS Patient Register count and the 2011
Census estimates for men and women respectively aged 70-74. For both men and women, the
majority of local authorities show the difference between the two sources to be within three per
cent of each other (71 per cent of local authorities for men and 84 per cent of local authorities for
women). This is in contrast to the 20-24 age group where only 17 per cent of local authorities for
men and 16 per cent of local authorities for women show a difference between the two sources as
being within three per cent of each other.
For the 70-74 age group, the local authorities that show a larger difference than three per cent
between the two sources are often in urban areas. Both men and women see the majority of the
local authorities within Greater London as having a greater difference than three per cent between
the two sources.
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
34
Map 6. Percentage difference between the 2011 NHS Patient Register and the 2011 Census
by local authorities in England and Wales by males aged 70-74 years
Source: NHS Patient Register 2011, Census 2011
Contains National Statistics data © Crown copyright and database right 2012
Contains Ordnance Survey data © Crown copyright and database right 2012
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
35
Map 7. Percentage difference between the 2011 NHS Patient Register and the 2011 Census
by local authorities in England and Wales by females aged 70-74 years
Source: NHS Patient Register 2011, Census 2011
Contains National Statistics data © Crown copyright and database right 2012
Contains Ordnance Survey data © Crown copyright and database right 2012
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
36
Further work comparing NHS Patient Register counts to Census 2011 estimates at local authority
level has been carried out by ONS as part of the quality assurance process for Census 2011. NHS
Patient Register data at local authority level is available on the ONS website on the Local Authority
Quality Assurance page. Detailed information about the Census 2011 quality assurance process
used by ONS can be obtained on the ONS website on the Quality assurance and methodology
page.
7 Further considerations and summary
The comparison between the 2011 NHS Patient Register count and the 2011 Census estimates
gives us a greater understanding of the quality of the NHS Patient Register. It is evident that the
gaps that exist between the two sources vary with age and sex. It is also clear that at the local level
patterns are much more variable and depend on particular local circumstances. Higher levels of
international migration have been shown to contribute to net over coverage in the Patient Register
(Smallwood & De Broe 2009). For areas where the census estimates exceed the NHS Patient
Register, a specific population which the NHS Patient Register does not cover, e.g. Armed Forces,
is likely to be the reason. In relation to sex differences, it was found that, at a national level, men
contributed more toward the 2011 NHS Patient register count exceeding the 2011 Census estimate
than women. Further, the age span (22-63 years) during which men on the patient register
exceeded 2011 Census estimates was greater than it was for women (20-48 years).
The comparison between the 2011 NHS Patient Register count and the 2011 Census estimates
can only highlight the difference between the two sources and not what proportion of it is
attributable to under coverage and over coverage. Despite only a small number of local authorities
being lower than the census it cannot be assumed that the NHS Patient Register only suffers from
over coverage in the majority of local authorities. It is highly likely that under coverage is
experienced among specific groups of the resident population but that the more prevalent issue of
over coverage in fact masks this. Further research using ‘anonymised’ data linking will help us to
understand this issue better.
Another aspect for consideration is whether some of the patterns observed in sex ratio data can be
accounted for by exploring the various NHS screening programmes to determine how these may
affect list cleaning differently according to age and gender. This further research will allow ONS to
improve its use of the Patient Register data within the Beyond 2011 Programme.
8 Future changes to the NHS Patient Register
So far this report has focussed upon the present state of the NHS Patient Register. However, in
this section, three known future administrative/structural changes are highlighted which were
identified as potentially having implications for the NHS Patient Register and, consequently, for the
Beyond 2011 Programme.
Personal Demographics Service (PDS)
The PDS is a national electronic database of demographic information for persons in England. In
time (unlikely to be sooner than 2015) it will integrate with, and ultimately replace, the following
NHS services/systems: NHS Strategic Tracing Service; NHS Number for Babies; NHSCR and the
NHAIS (‘Purpose and benefits of the PDS’ 2012). There is also an intention to integrate the system
into GP practices such that when a person registers with a GP an authorised user can perform a
search to immediately attempt to determine the patient’s NHS number. However, ongoing issues
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
37
with the development of this system mean there is currently no fixed date for when the PDS will
become the primary source of patient demographic information in England. A similar, but separate,
system is currently being developed in Wales and is administered by the NHS Wales Information
Service. The likelihood that the PDS will eventually replace the NHS Patient Register may have
positive implications for Beyond 2011, in terms of the availability of additional useful variables e.g.
first language.
Disbanding of Audit Commission
The Audit Commission will be disbanded in the next few years, leaving a question mark over where
the data matching expertise for future quality initiatives will be sourced (Audit Commission 2012).
With respect to Beyond 2011 this may mean future EPR extracts received by ONS may not have
been submitted to a recent, full-scale, list de-duplication exercise.
Abolition of PCTs
PCTs are expected to ‘cease to exist by 2013’ (Department of Health ‘Equity and Excellence:
Liberating the NHS’, p.34) and their primary care responsibilities will transfer to NHS
Commissioning board or Clinical Commissioning groups. It is too soon to say whether this will have
an impact upon data quality of future NHS Patient Register datasets, though, as the possibility
cannot be ruled out, this will need investigating when more information becomes available.
9 Conclusions and Recommendation for use in Beyond 2011
The present report has illustrated that the NHS Patient Register is likely to be a key data source for
Beyond 2011 as it:
•
has very high level of population coverage (based on residential base).
•
provides basic demographic information on age and sex
•
has good quality data with very low levels of missing values for key variables
•
includes information on first registration of international migrants (flag 4)
•
linkage with other administrative data sources is possible using a combination of
anonymised key variables; e.g. surname, date of birth and address information
•
can be obtained for a comparable reference period
Comparisons between the NHS Patient Register and the 2011 Census estimates have revealed
that for some age-sex groups (e.g. males aged 20-30 years), there are greater differences
between the two sources than for other age-sex groups (e.g. males aged 65+); highlighting where
other sources and/or a survey may in particular be needed to help estimate the size of the
population in Beyond 2011 administrative data based options.
Overall, the NHS Patient Register provides very broad coverage of persons within England and
Wales and should prove to be an important source of data for the Beyond 2011 Programme.
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
38
Glossary
EPR
Enhanced Patient Register
GP
General Practitioner
NDRI
National Duplicate Registration Initiative
NHS
National Health Service
NHAIS
National Health Applications and Infrastructure Services
NHSCR
National Health Service Central Register
NHSIC
National health Service Information Centre
ONS
Office for National Statistics
PCT
Primary Care Trust
RBD
Registrars of Births and Deaths
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
39
References
Administrative Data Liaison Service GP Patient Register Dataset (2012) retrieved 21st August 2012
Audit Commission (2012) National duplicate registration initiative 2009/2010 – National report.
Audit Commission (2006) National duplicate registration initiative 2004 – National report.
Department of Health (2011) Technical Guidance for the 2012/13 Operating Framework.
Downloaded 23rd July 2012
Department of Health (2010), Equity and Excellence: Liberating the NHS. Retrieved 2nd August
2012
National Health Service Family Doctor Services Registration Form (GSM1)
National Health Service (2009) ‘NHS Information Centre takes control of NHS Central register’
Retrieved 21st August 2012
Office for National Statistics (2012a) Census first release figures. Retrieved 21st August 2012
Office for National Statistics (2012b) 2011 Census: Number of non-UK short-term residents by sex,
local authorities in England and Wales. Retrieved 11th October 2012
Office for National Statistics Longitudinal Study
Office for National Statistics Beyond 2011 Reports and Publications
Office for National Statistics Local authority quality assurance
Office for National Statistics Quality Assurance and Methodology
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a Postcode Best Fit Methodology October 2011.
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Appendix A: NHS Family Doctor Services Registration Form (GSM1)
Beyond 2011 : Administrative Data Sources Report: NHS Patient Register
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